Techniques for recognizing a fingerprint, a palm, a voice, a retina, an iris, a face, a blood vessel or the like are used as general body authentication means. In the case of a fingerprint, a retina or a blood vessel among them, authentication is achieved using a fingerprint, capillary vessels of an eyeball or a venous pattern.
For example, a fingerprint refers to a pattern of ridges created in the form of a certain pattern from the contour of the epidermis of a person's fingertip. Fingerprints created on fingers of different persons are formed in patterns different from one another, and a fingerprint that has been created once does not change. Due to the features of the fingerprint, i.e., fingerprints are created in different patterns on fingers of different persons and do not change once they have been created, the fingerprints are frequently used for personal authentication these days. Accordingly, methods of recognizing a user's fingerprint are being developed recently for personal authentication.
A system for recognizing a user's fingerprint may be configured to include a contact member formed of a transparent material with which a finger of a user is to be brought into contact, an illumination unit for radiating light on the finger of the user in contact with the contact member, a camera unit for photographing the finger that is in contact with the contact member and irradiated with the light, and a recognition unit for recognizing and comparing the fingerprint using a fingerprint image generated by photographing the finger using the camera unit. At this point, the recognition unit may extract a pattern or the like of the fingerprint from the fingerprint image and then recognize and compare the fingerprint.
However, the image generated by photographing the finger may be distorted since the system is basically a two-dimensional type and the light is not radiated uniformly due to the ridges or the like on the finger in a state where the finger is in contact with the contact member when the finger is photographed through the camera, or the image generated by photographing the finger may be distorted depending on states of the finger of the user (e.g., states where the finger is wet or dry or the fingerprint is partially lost). That is, if a fingerprint is recognized using a distorted image, there is a problem in that the recognition unit does not easily extract the pattern of the fingerprint, resulting in lowered accuracy of fingerprint recognition.
Accordingly, there is a need for development of a device and method for measuring a three-dimensional shape, wherein a three-dimensional shape of each part of a body can be measured or the accuracy of recognition can be improved in use as a body authentication means.
Meanwhile, although a conventional three-dimensional measurement method computes a shape through a pin contact on a surface of an object to be measured in a contact manner, a non-contact type three-dimensional measurement method using laser and light is utilized in a variety of industries with the development of new techniques. However, this has a disadvantage in that there is deterioration of portability or convenience since a measurement should be made in a state where a measurement device and the object to be measured are fixed, due to vulnerability to vibration or the like.